Reaction of potassium permanganate with oxalic acid in acidic medium is an example of auto catalysis. Catalyst in this reaction is

Reaction in which the product formed (or) the intermediate formed acts like a catalyst is classified as auto catalysis reaction.${\mathrm{MnO}}_4^{-}+{\mathrm{C}}_2{\mathrm{O}}_4^{-2}\stackrel{{\mathrm{H}}^{+}}{\to }{\mathrm{Mn}}^{+2}+{\mathrm{CO}}_2$  ;

Mn⁺² formed in the process acts like a catalyst.